The oxidation-reduction chemistry of manganese (II, III, IV) complexes is to be investigated by electrochemical, spectroscopic, and stopped-flow methods in aqueous and in aprotic solvents. The goal of the research is to discover manganese complexes and solution conditions which result in oxidation-reduction chemistry that mimics that of mitochondrial superoxide dismutase (SOD) and of the water-oxidizing species associated with photosystem II in green-plant photosynthesis. The ligands proposed for study are gluconate ion, triethanolamine, pyrophosphate ion, bipyridyl, and 8-quinolinol. Determination of the oxidation-reduction thermodynamics, reaction kinetics, and solution structures for the various manganese complex-solvent systems will be the means of characterization. Studies of the reaction chemistry and the chemistry of the reaction products for the various manganese complexes in combination with O2, O2-, and H2O2 are a major part of the project. Manganese systems analogous to the Haber-Weiss Fe(II)-H2O2 reaction for the formation of hydroxyl radicals are to be sought and characterized in terms of kinetics and mechanisms. BIBLIOGRAPHIC REFERENCES: "Redox Reactions of Di-mu-Oxo Bridged Binuclear Manganese (IV) and -(III), Complexes," M. M. Morrison and D. T. Sawyer, J. Amer. Chem. Soc., 99, in press (Jan., 1977). "One Electron Mechanism for the Electrochemical Reduction of Molecular Oxygen," D. T. Sawyer and E. T. Seo, Inorg. Chem., 16, in press (Feb., 1977).